Antenna system



Dec- 285 1948- F. o. CHI-:sus E-AL 2,457,127

ANTENNA SYSTEM med June 27, 1945 I f l 2 sham-sheet 1 INVENTORS Patented Dec. 28, 1948 orifice ANTENNA SYSTEM Frank 0. Chesus, Jackson Heights, and Frank G.

Thomas, Islip, N. Y., assignors to Federal Telephone and Radio Corporation, New York, N. Y.,

a corporation of Delaware l lAppleman .nine 2v, 1945, serial No. 601,800

1 24 Claims.

The present invention relates to goniometers and particularly those adapted for use at very high frequencies.

Inductive goniometers have not been extensively used for very high frequencies primarily because either the coemcient of coupling between the rotor and stator was so low that there was a high insertion loss and/or where the insertion loss was small, the stator eld distribution was non-uniform and therefore contributed to goniomitor error. y

An object of the present invention is the provision of an improved inductive goniometer, particularly adapted for operation at very high frequencies.

Another object of lthe present invention is the provision of a. goniometer of relatively high accuracy, and particularly adapted for operation a-t very high frequencies.

Another object of the present'invention is the provision of a goniometer in which the rotor and stator are relatively closely coupled and which provides for accurate operation over a relatively between the antennas and the direction nding receiver.

Still another object of the present invention is the provision of an improved direction liinder employing goniometers embodying our 'invention.

Other and further objects of our invention will become apparent and the invention will be best 2 Referring now to Fig. 1, the goniometer there illustrated,A generally designated by the numeral I is comprised of two coaxial annular members or rings 2 and 3 of conductive material, the outer ring 2 being the stator and the inner ring 3 being the rotor. The rings 2 and 3 are each in Athe form of a completely closed single loop. The stator Zand the rotor 3 lie in the same or substantially the same plane adjacent each other with the rotor 3 adapted to rotate in said plane about a central axis l which is perpendicular to said plane. A pair of leads 5 and 6 are connected to substantially diametrically opposite points on saidA rotor at one of their ends and the other ends are adapted to be coupled to the direction ilndingreceiver.l

The antenna system is connected to substantially symmetrically and equally spaced points on the stator 2 with each of the individual antenna units coupled to one of said points. For example, in an Adcock array of the type having four spaced antenna umts l-Hi arranged to produce a crossed figure-of-eight reception pattern y with antenna units l and 9 forming one of said pairsy and antenna units 8 and l0 forming the other pair which is crossed at right angles to the iirst pair, all of said units being substantially equi-distant from a central point, antenna units 'i and 9 are connected to diametrically opposite points on the stator 2 while antenna units 8 and I0 are likewise connected to diametrically opposite points on said stator 2, but the latter opposite points are at 90 to said rst-mentioned points. Of course, it is to be understood that the understood from the following description 'thereof, reference being had to the drawings, in which: Fig. 1 is a schematic diagram of a goniometer embodying our invention, showing the connection of the goniometer to a direction nder antenna other type goniometer embodying our invention.

antenna arrangement here described is only by way of example and that numerous other types of antenna arrangements, such as for example, crossed loops or crossed dipoles as well as other antenna systems not producing a figure-of-eight, may likewise be connected to equally and/or' symmetrically spaced points on the stator. Furthermore, three symmetrically disposed antenna v units may be connected to the stator at three symmetrical points on the stator, or four antenna units may be connected to symmetrical but no1: v

equallyl spaced points on said stator. Assuming a wave to be approaching the antenna. system in such a direction that at a given aca-1,121

and in this position a maximum transfer of energy would occur between the stator 2 and rotor 3. However, if the rotator rotates so that the leads and 3 are in the position indicated by the broken lines I I and i2, the minimum transfer energy will occur between the stator and rotor. In the foregoing analysis, no reference has been made to the current flowing from antennas 1 and 9. In the conventional antenna system or in the antenna system of the type hereinabove described, when a wave is approaching so as to induce a current flow from antenna 8 to antenna I0, either no voltage will be induced in antennas 1 and 8 or the voltages that are induced will be the same so that when these antennas l and 49 are connected to the stator 2, they tend to drive current in opposite directions through the stator and thereby neutralize each other's effect.

Referring now to Fig. 2, a physical embodiment of the type of goniometer shown schematically in Fig. 1 is there illustrated. The stator 2 is in the form of a trough within which the rotor 3 rotates thereby producing extremely closely coupling approaching unit coupling. The rotor 3 is mounted on a disc I3 of insulating material which is carried on arotatable shaft I4, said shaft being hollow so that the leads 5 and 8 may be brought into said shaft and carried therein.

IShaft I`4is driven by a motor IE which may be also employed to control the generation of the sweep of an oscilloscope I8 at the output of a direction finding receiver I1 so as to synchronize the sweep with the rotation of rotor 3. To provide for coupling of leads li and 8 to the direction nding receiver I1, a coupling transformer I8 is provided having a rotating conductive member I3 in the form of a conductor split at 23, the

leads 5 and B being carried through shaft I4 and connected to the free ends of the rotor member I9 at said split 23, the rotor member I9 being mounted on a disc 2l which is also carried on shaft I3 whereby the rotor member I9 rotates at the same rate as the rotor 3. Rotator member I3 rotates within the trough of a coaxial circular conductive stator member 22 similar to stator 2 except that stator member 22 is also split and the ends of said stator members 23 and 24 at said split are connected by leads 25 and' 28, respectively, to the direction finding receiver I1.

Assuming that instantaneous current conditions prevail in the goniometer of Fig. 2 such as are indicated by the arrows in Fig. 1, current tends to flow through leads 5 and 6 in the direction indicated by the arrows, the current also flowing through rotor I9. The current flowing through rotor I 9 induces opposite currents on the inner surface of the stator 22, these currentsv then causing current to flow through leads 2E and 2B as indicated by the arrows. Thus, the coupling transformer I8Y serves to couple the rotating leads 5 and 6 to the stationary leads 23 and 26 and thence to the direction finding receiver.

Under certain circumstances the inductance of a single closed loop stator or rotor may be insufllcient. particularly at the lower wavelengths a single loop while the rotor 28 is in the form of a double loop. The rotor 28 consists of four semi-circular strands of wire 29-32, strands 29 and 30 `being on one side of the line defined by a diameter between leads 5 and 6 and strands 3| and 32 being on the other side. It will be seen that in order to have the current induced in strands 28 and 30 flowing in the same direction, these two strands must have their opposite ends connected together as, for example, by lead 33 while the same function is performed for strands 3| and 32 by lead 34. Leads 33 and 34 by reason of their location do not materially interfere with the operation of the goniometer. The current flow is indicated by the arrows in said figure.

While in Fig. 3 the rotor is shown as being doubled, it is also apparent that the same construction may be used to provide a doubled stator which is particularly desirable as the wavelengths are increased to provide the additional inductance needed for proper impedance matching. Furthermore, while the doubled rotor or stator may be in the form illustrated in Fig. 3, other convenient forms may beused in place thereof. For example, in Fig. 4 the doubled rotor 35 consists of two semi-circular coaxial lines 36 and 31 arranged in the form of a circle, lead 6 being.. connected to one end of the inner conductor 38 of coaxial line 31 at one point of said circle, with the inner conductor 39 of line 36 connected to the outer conductor 40 of line 31 at thesame point of said circle. At a diametrically opposite point of said circle, lead 5 is connected to the free end of inner conductor 39 while the free end of inner conductor 38 is connected to the/"outer conductor 4I of line 36. Also, outer conductors or when an impedance transformation is desired between the antennas and the direction nding receiver. Under such circumstances, the loop 40 and 4I are interconnected at their free ends by conductor 42 located along a diameter of the circle. It will be seen that the induced current flow in the rotor 36 is in a series circuit as indicated by the arrows. Viewed, however, from the circle as constituted by the two outer conductors 43 and 4I, the paths of induced currents therein are generally speaking parallel over the two semicircles, so that the effect of a doubled loop is produced, thus increasing the inductance of the rotor 35. A similar construction may be used for the stator.

While in Figs. 1-3, we have illustrated the rotor as arranged withinv the stator, it will be apparent that the rotor may be arranged adjacent the stator in a plane parallel to the statorv or, if desired, two stators 42 and 43 may be used, each coupled to a separate pair of antenna units, as is illustrated, for example, in Fig. 5, in which antennas 8 and Ill are connected to one .stator and antennas 1 and 9 are connected to the other stators in a position at right angles to the connections of the first stator. In some cases the stators may be similar in construction to that shown in Fig. 4. The rotor 44 is positioned betweenA the two stators in planes parallel to said stators and may be rotated by shaft I4 with the various leads passing through said shaft to a coupling transformer of the type designated by numeral I8 in Fig. 2. 1

While we have described various specific embodiments of our invention, it will be apparent to those versed in the art that numerousmodiications may be made in the structures without departing from the teachings of our invention. For example, the rotor 3 in Fig. 1, need not rotate as a unit but the leads 5 and 6 may be rotated about a fixed ring to produce the same effect as if the entire rotor 3 were rotated. Likewise it will b`e apparent that the rotor and stator may be changed'in position, and the rotor may be in the form of a trough. Furthermore, while we have described the antenna units as connected at various points to the stator and the leads 5 and 6 connected to the rotor. it will be apparent that these connections could be replaced by couplings other thangalvanic. Furthermore while, for `the sake of clarity, the leads 5 and 6 have been shown as single conductors. it will be apparentto those versed in the art that in actual practice these conductors may be in the form of coaxial lines. Various other modiiications will readily occur to those versed in the art. Accordingly, while we have described above the principles of our invention in connection with specific apparatus, and particular modications thereof, it is to be clearly understood that this description is made only by way of example and not as a limitation on the scope of our invention as dened in the accompanying claims.

We claim:

1. A goniometer comprisinga pair of conductive members inductively related by a substantially uniform field, one of said members havingv coupling means connected to substantially sym,- metrically spaced points thereon, a pair of leads coupled to symmetrical points on the other conductor, and means for eiectively rotating the position of said points of said coupling to said other member relative to said one member.

2. A goniometer for coupling to an antenna system comprising a pair of coaxial annular conductive members positioned adjacent each other,

one of said members adapted to be separately connected to said antenna system at substantially symmetrically spaced points thereon, a pair of leads coupled to substantially diametrically opposite points on the other member, and means for effectively rotating the position of said coupling to said other member relative to said one member. l

3. A goniometer comprisinga pair ofcoaxial annular conductive members positioned adjacent each other, a, lplurality of input leads connected to one of said members at equally spaced points thereon, a pair of output leads connected to sub- 8. A goniometer according to claim 2 wherein each of saidmembers is in the form of a completely closed single loop.

9. A goniometer according to claim 1 wherein one of said members is in the form of a trough with the other member arranged within Ysaid trough.

10. A goniometer for an antenna system comprising a pair of coaxial annular conductive members positioned adjacent each other, one member being adapted to be separately coupled to the antenna system at substantially symmetrically spaced points on said one member, a pair of leads coupled to substantially diametrically opposite points on the other member, and means for pro-l ducing effective relative rotation between said members.

11. A goniometer for an antenna comprising a coaxial annular conductive Vstator and annular conductive rotor `positioned adjacenteach other, said stator being adapted to be separately coupled to the antenna system at substantially symmetrically spaced'points on said stator, a pair of leads coupled to substantially diametrically opposite points on said rotor, and means for rotating said rotor.

12. A goniometer according to claim 10 wherein said members lie within the same plane, one of said members being inside the other.

13. A goniometer according to claim l0 wherein said members lie in parallel planes.

14. A goniometer according to claim 10 wherein one of said members is in theform of a trough with the other mem-ber arranged within said trough.

l5. A goniometer according to claim 10 wherein said members are each in the form of a com pletely closed single loop.

16. A goniometer according to claim 11 wherein saidstator is in the form of a trough with the rotor rotating within said trough.

17. A goniometer according to claim 11 and further including vstationary lead and means for coupling said pair of leads to said stationary leads.

- 18. A goniometer according to claim 11 further including a pair of stationary leads and means for coupling said leads to said stationary leads, said means comprising a pair of coaxial split rings arranged immediately adjacent each other, one of said rings being rotatable, said leads being connected to the free ends thereof at said split, and a pair of stationary leads connected to the free ends of the other ring at its split, the rotatable ring being adapted to rotate synchronously with said rotor.

19. A goniometer according to claim 1 wherein said other member comprises a pair of semicircular coaxial lines arranged in the form of a circle with the inner conductor of one line connected to the outer conductor of the other at one point of said circle, and at the diametrically opposite point of said circle the outer conductor of said one line is connected to the inner conductor of said other line, with said leads being connected to the free ends of the inner conductors of each line.

20. A goniometer for an antenna system `comprising a pair of conductive members inductively related by a substantially uniform eld, one of said members having means for coupling said antenna system to substantially symmetrically spaced points thereon, a pair of leads connected at symmetrical points on the other conductor, thereby eiecting connection between said leads over generally parallel paths in said other memf ber, means for eilectively rotating the position of said coupling to said other member relative to said one member, and means for effecting impedance transformation between said members comprising additional series circuit connections to the conductors of said one member, whereby induced currents make repeated traversals of said paths.

21. A goniometer according ,to claim 20, wherey in the rotating means serves to rotate said other member, and the impedance transformation means is applied to the rotated member.

22. A goniometer according to claim 20, wherein the means for eiecting impedance transformation includes return loops in said paths.

23. A goniometer according to claim 20, where in the means for effecting impedance transformation includes coaxial lines in said paths.

24. A direction nder collector system cornprising two crossed pairs of spaced antenna units symmetrically disposed about a central axis, and a. goniometer comprising three coaxial annular conductive members positioned adjacent each other and lying in parallel planes, means coupling the antenna units of one pair to diametrically opposite points on the upper of said members,

means coupling the antenna units of the other D811' to diametrically opposite points on the lower member which points are at right angles to said first mentioned points, a. pair of leads coupled to substantially diametrically opposite points on the middle member. and means for eiectively rotating the position of the points of connection of said leads relative to said upper and lower members.

FRANK O. CHESUS. FRANK G. THOMAS.

No references cited. 

